1. Field of the Invention
The present invention relates to a weather strip having a trim part of a substantially U-shaped cross section.
2. Related Art
In general, for example, a weather strip made of a rubber material such as EPDM is provided on a peripheral portion of a door opening in a body of a vehicle such as an automobile. The weather strip is formed into an elongated shape having a constant cross-sectional shape by extrusion molding. In addition, as shown in FIG. 6A, a weather strip 51 has a trim part 52 that is held by being fitted on a flange along a peripheral portion of the door opening and a hollow seal part 53 that is provided so as to protrude from the trim part 52. The trim part 52 includes a bottom portion 54, and an interior side wall portion 55 and an exterior side wall portion 56 which are extend substantially in parallel from the bottom portion 54 and is formed into a shape having a substantially U-shaped cross section as a whole. A metallic insert 57 is embedded in the interior of the trim part 52 in order to hold the substantially U-shaped cross section.
In assembling the weather strip 51 like this to a corner portion of the peripheral portion of the door opening in the vehicle body, the weather strip 51 needs to be bent relative to a longitudinal direction thereof so as to conform to a curved shape of the corner portion. Here, when the curvature of the curved shape is large, there may exist a risk that a so-called open deformation of the trim part occurs in which an opening in the substantially U-shaped cross section of a trim part 58 opens as shown in FIG. 6B. In a weather strip 59 in which the open deformation of the trim part occurs, a gap is generated between the flange and the weather strip itself, leading to drawbacks that the external appearance is deteriorated and that the holding force is reduced to facilitate the dislocation of the weather strip.
Then, in order to make the opening width of the trim part corresponding to the corner portion narrower than that of the trim part corresponding to the straight portion, there have been considered countermeasures in which the opening width is made to vary depending upon longitudinal positions of the weather strip (for example, refer to Japanese Patent No. 2750641) and in which clamping or compressing work is applied to the portion where the open deformation of the trim part occurs afterwards.
When varying the opening width partially, however, the manufacturing process becomes complicated and the manufacturing facility also becomes complicated. By this structure, there may be caused a risk that the production costs of weather strips are increased. Moreover, there have existed cases where only narrowing the opening width is not sufficient as the countermeasures against the open deformation of the trim part. In addition, also in a case where the compressing or clamping work is performed afterwards, since a step for the work is added, there exists a risk that the production costs are increased.